Drop on demand ink jet technology for producing printed media has been employed in commercial products such as printers, plotters and facsimile machines. Generally, an ink jet image is formed by selective placement on a receiver surface of ink drops emitted by a plurality of drop generators implemented in a printhead or a printhead assembly. For example, the printhead assembly and the receiver surface are caused to move relative to each other and drop generators are controlled to emit drops at appropriate times, for example by an appropriate controller. The receiver surface may be a transfer surface, the image printed upon it is subsequently transferred to an output print medium such as paper.
A known ink jet drop generator structure employs an electromechanical transducer to displace ink from an ink chamber in a drop forming outlet passage, and it may be difficult to control drop velocity and/or drop mass.